Young adult (18-24-year-old) Black, Hispanic, and white men-who-have-sex-with-men (MSM) have among the highest incidences of HIV infection in the United States (US), yet have low HIV testing rates. New approaches to encourage and facilitate HIV testing are needed to reduce the impact of the HIV epidemic among this at-risk population. In this innovative, early-stage, developmental R21 study, we will evaluate a new approach to increase HIV testing among young adult Black, Hispanic, and white MSM. This new approach will evaluate acceptance and utilization of a new rapid HIV self-test that was recently approved by the US Food and Drug Administration, and as well as usage of a MSM social-networking website to facilitate HIV testing and dissemination. The entire study will be internet-based, in regards to recruitment, enrollment, follow-up, and acquisition of HIV tests, which is appropriate given the high level of familiarity, use, and comfort with the internet among young adult Black, Hispanic, and white MSM. In Stage I, we will survey a large sample of young adult Black, Hispanic, and white MSM social-networking website users and assess their acceptance, facilitators/barriers to use, utilization, preferences, and opinions regarding a new rapid HIV self test, as compared to conventional home-based HIV testing or medical or community-based HIV testing. In Stage II, we will go beyond the perspectives evaluated in Stage I and directly evaluate through a randomized, controlled trial if testing uptake is greater and time to initiation of testing is shorter for participants randomly assigned to use the rapid HIV self-test, as compared to those assigned to undergo conventional home-based HIV testing or medical or community-based HIV testing. In Stage III, we will assess if the experience with using the rapid HIV self-test, as compared to the other testing approaches, encourages these young adult Black, Hispanic, and white MSM to invite their online or offline contacts to use this new type of test. We will also determine if there are differences across the racial/ethnic groups in regards to these outcomes, which might impact the effectiveness of testing approaches. This R21 project is highly significant and innovative because it investigates if HIV testing can be facilitaed on a national scale among a higher risk population with historically low HIV testing rates (young adult Black, Hispanic, and white MSM) through social media recruitment and a new method of HIV testing. The potential public health impact of this study would be in the creation of a new approach to improving HIV testing through an internet-based, social-network-facilitated recruitment and dissemination of new HIV testing technologies. The results of this R21 and lessons learned will be used to initiate a larger and more sophisticated RO1 study of other internet-based social networks to facilitate HIV testing among MSM and other populations.